[SOLVED] Using a class object as a parameter within the same class object

Using a class object as a parameter within the same class object

I'm having trouble with a custom class module called "Spectrum"

The following line of code should subtract spectrum "B" from spectrum "A" directly modifying the private variables within "A".

    A.subtract(B)

But at run-time, I get a "Run-time error '438': Object doesn't support this property or method"

Here is the subroutine from the "Spectrum" custom class module:

    Private pYValues(1 TO 10000) as Double
    Private pIndex as Integer

    Public Sub Subtract (Value as Spectrum)
        Dim i as Integer
        For i = 1 to pIndex
            pYValues(i) = pYValues - Value.YValues(i)
        Next i
    End Sub

    Public Property Get YValues(index as Integer)
        YValues = pYValues(index)
    End Property

Here is the actual snippet of code I am trying to run from a seperate module:

    Sub testArrayLoading()
        ' Create a file dialog object
        Dim fd As FileDialog

        ' Choose destination folder (global resource variable!)
        Set fd = Application.FileDialog(msoFileDialogOpen)
        fd.Show

        ' Create a spectrum object
        Dim mySpectrum1 As Spectrum
        Dim mySpectrum2 As Spectrum
        Set mySpectrum1 = New Spectrum
        Set mySpectrum2 = New Spectrum

        ' Populate each spectrum with data
        mySpectrum1.Import (fd.SelectedItems(1))
        mySpectrum2.Import (fd.SelectedItems(1))

        ' Subtract one spectrum from the other
        mySpectrum1.Subtract (mySpectrum2)
    End Sub

Am I not able to use a class object as a parameter within the same class? or am I supposed to be using a property instead of a sub-routine?

So far I have tried using ByVal and ByRef, and switching the subroutine to a Public Property Set instead. Neither has worked for me. I think I'm just missing something in terms of my understanding of passing custom class objects as parameters.

Thanks for the help,

Michael

Solution

Parenthesis. This line...

mySpectrum1.Subtract (mySpectrum2)

...should be either...

mySpectrum1.Subtract mySpectrum2

...or:

Call mySpectrum1.Subtract(mySpectrum2)

See What does the Call keyword do in VB6?